The present invention relates generally to an optical tape cassette for vast information storage and an optical tape cassette player for recording/reproducing desired information using the tape cassette, and more particularly to an optical tape cassette and player which are easy to handle and are practical for large-capacity auxiliary memories for computers or optical video cassette recorders (OVCR) for home use.
Generally, an optical recording medium has a higher writing density than that of a magnetic recording medium, and has a longer life because a recording/reproducing optical pickup has no contact with the medium. For vast storage of information such as that needed for computers, satellites or VCRs used with high definition television (HDTV), a large-capacity recording medium is required. Therefore, optical recording media are preferable to magnetic recording media, and more attention is being paid to tape-type optical recording media which have a wider recording area than the disk-type whose recording area is considered to be currently at maximum.
U.S. Pat. Nos. 4,525,828, 4,807,213 and 4,939,715 disclose systems for performing the recording/reproducing of information using tape-type optical recording media. Owing to these patents, the practicality of auxiliary memory for computers or OVCRs for home use, using optical tape, is greatly increased. However, the following technical difficulties still exist in the construction of individual systems.
In U.S. Pat. Nos. 4,525,828 and 4,807,213, in which the apparatus are constructed to scan optical tape in a similar manner as that used for VCRs using a rotating drum having optical pickup elements, the disclosed optical tape travelling system as well as the drum is complicated to increase the size and cost of the apparatus which is in turn unsuitable for home use. Since an objective lens as one of the optical pickup elements is rotated along with the drum, focus/tracking servo operation is impracticable or nearly impossible, and since the optical tape is exposed (outside the cassette housing) during the recording/reproducing, hum frequently takes place due to gathered dust.
In U.S. Pat. No 4,939,715, an optical tape reel is installed in a drum and a recording/reproducing optical pickup is separately provided, greatly simplifying the driving method. However, the apparatus still has problems in realizing an optical tape cassette of high practical use. Further, since two optical tape reels and their respective reel driving motors are constructed to be driven with the drum, a driving motor for the drum carries a heavy burden. In addition, due to tension bars of the optical tape installed in the drum, the geometric center and the center of mass of the drum cannot be coincident and so the drum cannot be driven at high speed, contrary to the drum for VCRs. This makes the apparatus unsuitable for high-definition video recording.